Super-self-aligned contacts and method for making the same

ABSTRACT

A number of first hard mask portions are formed on a dielectric layer to vertically shadow a respective one of a number of underlying gate structures. A number of second hard mask filaments are formed adjacent to each side surface of each first hard mask portion. A width of each second hard mask filament is set to define an active area contact-to-gate structure spacing. A first passage is etched between facing exposed side surfaces of a given pair of neighboring second hard mask filaments and through a depth of the semiconductor wafer to an active area. A second passage is etched through a given first hard mask portion and through a depth of the semiconductor wafer to a top surface of the underlying gate structure. An electrically conductive material is deposited within both the first and second passages to respectively form an active area contact and a gate contact.

CLAIM OF PRIORITY

This application is a divisional application under 35 U.S.C. 121 ofprior U.S. application Ser. No. 11/956,305, filed Dec. 13, 2007, andentitled “Super-Self-Aligned Contacts and Method for Making the Same,”the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND

During semiconductor wafer fabrication, electrically conductive activearea contacts are formed between active areas at the substrate level ofthe wafer and electrically conductive interconnect lines located abovethe substrate level. Also, electrically conductive gate contacts areformed between transistor gate structures within the wafer andelectrically conductive interconnect lines located above the gatestructures. Conventional active area contact and gate contactfabrication methods have relied upon photolithographic techniques inwhich a photomask is used to project a light pattern onto a photoresistlayer deposited on the wafer, so as to transfer the pattern to thephotoresist layer, wherein the pattern defines various openings withinthe photoresist layer at which contacts are to be formed. The variouscontacts are required to be accurately aligned to the underlying activeareas and gate features for proper contact placement, and ultimately forproper device operation. Therefore, the photomask must be accuratelyaligned to the wafer to enable proper transfer of the contact patternonto the wafer.

As device sizes become smaller and their features become more closelyspaced on the wafer, contact placement and fabrication becomes moredifficult. For example, it becomes more difficult to satisfy theincreasing photomask-to-wafer alignment accuracy requirements.Therefore, it is of interest to seek methods by which contacts can bemore accurately placed and fabricated for devices having smaller andmore closely spaced features.

SUMMARY

In one embodiment, a method is disclosed for fabricating an active areacontact within a semiconductor wafer. In the method, a number of firsthard mask portions are formed over a corresponding number of underlyinggate structures, such that each first hard mask portion verticallyshadows a respective one of the underlying gate structures. Also in themethod, a number of second hard mask filaments are formed adjacent toeach of the number of first hard mask portions. A combined width of eachfirst hard mask portion and its adjoining second hard mask filaments isgreater than a width of the respective underlying gate structure. Also,a width of each second hard mask filament defines an active areacontact-to-gate structure spacing. The method further includes anoperation for etching a passage between facing surfaces of neighboringsecond hard mask filaments, and through a depth of the semiconductorwafer to an active area. Then, an electrically conductive material isdeposited within the passage to form the active area contact.

In another embodiment, a method is disclosed for fabricating a gatecontact within a semiconductor wafer. In the method, a first hard maskportion is formed over a gate structure within a section of thesemiconductor wafer, such that the first hard mask portion verticallyshadows the gate structure. Also, the first hard mask portion is formedto include substantially vertical side surfaces. Also in the method, asecond hard mask filament is formed adjacent to each side surface of thefirst hard mask portion. An etching operation is then performed to etcha passage through the first hard mask portion, and through a depth ofthe semiconductor wafer to a top surface of the gate structure. Duringthis etching operation, surfaces of the second hard mask filamentsadjacent to the vertical side surfaces of the first hard mask portionare revealed through etching of the first mask portion. The revealedside surfaces of the first hard mask portion define side surfaces of thepassage. The method then proceeds with an operation for depositing anelectrically conductive material within the passage to form the gatecontact.

In another embodiment, a method is disclosed for fabricating an activearea contact and a gate contact within a semiconductor wafer. The methodincludes an operation for depositing a photon absorption layer betweengate structures within a section of the semiconductor wafer, so as tosubstantially cover an area present between gate structures with thephoton absorption layer while leaving a top surface of each gatestructure uncovered. Then, a dielectric layer is deposited over both thephoton absorption layer and the top of each gate structure within thesection of the semiconductor wafer. The method continues with forming anumber of first hard mask portions on the dielectric layer and over thegate structures within the section of the semiconductor wafer. Eachfirst hard mask portion vertically shadows a respective one of the gatestructures. Also, each first hard mask portion includes substantiallyvertical side surfaces. The method then proceeds with forming a secondhard mask filament adjacent to each vertical side surface of each firsthard mask portion, such that each second hard mask filament has anexposed side surface. A width of each second hard mask filament definesan active area contact-to-gate structure spacing. The method alsoincludes an operation for etching a first passage between facing exposedside surfaces of a given pair of neighboring second hard mask filaments,and through a depth of the semiconductor wafer to an active area. Themethod further includes an operation for etching a second passagethrough a given first hard mask portion, and through a depth of thesemiconductor wafer to a top surface of the gate structure underlyingthe given first hard mask portion. Surfaces of the second hard maskfilaments adjacent to the vertical side surfaces of the given first hardmask portion are revealed through etching of the given first maskportion. These revealed surfaces of the second hard mask filamentsdefine side surfaces of the second passage. The method then proceedswith an operation for depositing an electrically conductive materialwithin both the first and second passages to respectively form theactive area contact and the gate contact.

In another embodiment, a semiconductor device is disclosed. Thesemiconductor device includes a linear gate structure having sidesurfaces and a top surface. A width of the linear gate structure isdefined by a perpendicular distance between the side surfaces of thelinear gate structure. The semiconductor device also includes a gatecontact disposed to electrically connect to the top surface of thelinear gate structure. The gate contact has a substantially rectangularhorizontal cross-section. Also, the gate contact is defined tosubstantially cover the width of the linear gate structure withoutextending substantially beyond either of the side surfaces of the gatestructure.

Other aspects and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings, illustrating by way of example the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an illustration showing a flowchart of a method forfabricating super-self-aligned contacts within a semiconductor wafer, inaccordance with one embodiment of the present invention;

FIG. 1B is an illustration showing an expanded view of operation 101 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 1C is an illustration showing an expanded view of operation 103 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 1D is an illustration showing an expanded view of operation 105 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 1E is an illustration showing an expanded view of operation 107 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 1F is an illustration showing an expanded view of operation 109 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 1G is an illustration showing an expanded view of operation 113 ofFIG. 1A, in accordance with one embodiment of the present invention;

FIG. 2A is an illustration showing a top view of the wafer portion, inaccordance with one embodiment of the present invention;

FIG. 2B is an illustration showing a vertical cross-section view of thewafer portion, in accordance with one embodiment of the presentinvention;

FIG. 2C is an illustration showing the an expanded view of a given gatestructure, in accordance with one embodiment of the present invention;

FIG. 3 is an illustration showing the photon absorption layer depositedover the wafer portion, in accordance with one embodiment of the presentinvention;

FIG. 4 is an illustration showing the upper portion of the photonabsorption layer removed to expose the top surfaces of the gatestructures, in accordance with one embodiment of the present invention;

FIG. 5 is an illustration showing the dielectric layer deposited overthe wafer portion, in accordance with one embodiment of the presentinvention;

FIG. 6 is an illustration showing the first hard mask layer depositedover the dielectric layer, and the negative photoresist layer depositedover the first hard mask layer, in accordance with one embodiment of thepresent invention;

FIG. 7 is an illustration showing the exposure of the wafer portion tothe vertically collimated, incoherent light, in accordance with oneembodiment of the present invention;

FIG. 8 is an illustration showing the wafer portion following removal ofthe non-cross-linked portions of the negative photoresist layer, inaccordance with one embodiment of the present invention;

FIG. 9 is an illustration showing the wafer portion following removal ofthe unprotected portions of the first hard mask layer, in accordancewith one embodiment of the present invention;

FIG. 10 is an illustration showing the wafer portion following removalof the remaining negative photoresist portions, in accordance with oneembodiment of the present invention;

FIG. 11 is an illustration showing the second hard mask layer depositedover the wafer portion, in accordance with one embodiment of the presentinvention;

FIG. 12 is an illustration showing the second hard mask filamentsadjacent to the first hard mask portions, in accordance with oneembodiment of the present invention;

FIG. 13 is an illustration showing the positive photoresist layerdeposited over the wafer portion, in accordance with one embodiment ofthe present invention;

FIG. 14A is an illustration showing an example active area contact maskused to pattern the positive photoresist layer, in accordance with oneembodiment of the present invention;

FIG. 14B is an illustration showing the vertical cross-section view A-Aof the wafer portion with the patterned positive photoresist layer, inaccordance with one embodiment of the present invention;

FIG. 15 is an illustration showing the vertical cross-section view A-Aof the wafer portion with the passages for the active area contactsetched therein, in accordance with one embodiment of the presentinvention;

FIG. 16 is an illustration showing the wafer portion following removalof the patterned photoresist layer, in accordance with one embodiment ofthe present invention;

FIG. 17 is an illustration showing the positive photoresist layerdeposited over the wafer portion, in accordance with one embodiment ofthe present invention;

FIG. 18A is an illustration showing an example gate contact mask used topattern the positive photoresist layer, in accordance with oneembodiment of the present invention;

FIG. 18B is an illustration showing the vertical cross-section view A-Aof the wafer portion with the patterned positive photoresist layer, inaccordance with one embodiment of the present invention;

FIG. 19 is an illustration showing the vertical cross-section view A-Aof the wafer portion with the passages for the gate contacts etchedtherein, in accordance with one embodiment of the present invention;

FIG. 20 is an illustration showing the wafer portion following removalof the patterned photoresist layer, in accordance with one embodiment ofthe present invention;

FIG. 21 is an illustration showing the wafer portion following removalof the first hard mask portions and the second hard mask filaments, inaccordance with one embodiment of the present invention;

FIG. 22 is an illustration showing the vertical cross-section view A-Aof the wafer portion with the metal layer deposited thereon, inaccordance with one embodiment of the present invention;

FIG. 23 is an illustration showing the vertical cross-section view A-Aof the wafer portion with the excess metal layer removed to leave theactive area contacts and the gate contacts, in accordance with oneembodiment of the present invention;

FIG. 24A is an illustration showing a top view of the wafer portionfollowing formation of the active area contacts and gate contacts, inaccordance with one embodiment of the present invention; and

FIG. 24B is an illustration showing an expanded view of an area, ascalled out in FIG. 24A, in accordance with one embodiment of the presentinvention.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process operations have not beendescribed in detail in order not to unnecessarily obscure the presentinvention.

FIGS. 1A-1G are illustrations showing a flowchart of a method forfabricating super-self-aligned (SSA) contacts within a semiconductorwafer (“wafer” hereafter), in accordance with one embodiment of thepresent invention. The SSA contacts fabricated according to the methodof FIGS. 1A-1G can be either active area contacts or gate contacts. Tofacilitate description, FIGS. 2A-24B illustrate physical representationsof a portion of the wafer as it is subjected to the operations of themethod of FIGS. 1A-1G. The method begins with an operation 101 forpreparing a wafer portion for the SSA contact process. FIG. 1B is anillustration showing an expanded view of operation 101, in accordancewith one embodiment of the present invention. As shown in FIG. 1B,operation 101 includes an operation 115 for providing the wafer portionupon which the SSA contacts are to be fabricated.

FIGS. 2A-2C are illustrations showing an exemplary wafer portion 200provided in operation 115. It should be understood that the exemplarywafer portion 200 is provided by way of example for the purpose ofdescribing the SSA contact fabrication method of FIGS. 1A-1G. It shouldbe further understood that the SSA contact fabrication method disclosedherein is not to be limited to use with the particular exemplary waferportion 200. Moreover, it should be appreciated that the SSA contactfabrication process disclosed herein can be performed on essentially anysemiconductor device or semiconductor wafer within which one or moreactive area contacts and/or one or more gate contacts are to be defined.

FIG. 2A is an illustration showing a top view of the wafer portion 200,in accordance with one embodiment of the present invention. FIG. 2B isan illustration showing a vertical cross-section view of the waferportion 200, in accordance with one embodiment of the present invention.The vertical cross-section view (A-A) of FIG. 2B corresponds to thevertical cross-section of the wafer portion 200 at a locationcorresponding to bracket A-A in FIG. 2A. The wafer portion 200 includesa number of gate structures 205 defined thereon in a parallelorientation with respect to each other. FIG. 2C is an illustrationshowing an expanded view of a given gate structure 205, in accordancewith one embodiment of the present invention. It should be understoodthat the given gate structure 205, as shown in FIG. 2C, isrepresentative of the other gate structures 205 within the wafer portion200.

Each gate structure 205 is defined as a linear gate structure having acentral conductive region 219, a top region 217, and sidewall spacers215. In various embodiments, the central conductive region 219 can beformed of polysilicon, metal, or essentially any other suitableelectrically conductive material. The top region 217 is formed of anelectrically conductive material that is capable of reflecting photons,such a those of incoherent light. For example, in one embodiment, thetop region 217 is formed of NiSi₂. In various embodiments, the sidewallspacers 215 can be formed of essentially any suitable material. Forexample, in one embodiment, the sidewall spacers 215 are formed ofSi₃N₄.

Each gate structure 205 is defined as a linear gate structure having atop surface 222, substantially parallel side surfaces 220, a width 216defined perpendicularly between the side surfaces 220, and a length 218extending perpendicular to the width 216 along the top surface 222. Inthe exemplary wafer portion 200, for ease of description, each lineargate structure 205 is shown to have a length approximately equal to thelength 218. However, it should be understood that the various gatestructures 205 are not required to have the same length. For example,any number of the linear gate structures 205 may be segmented to includea number of breaks, depending on the circuit function to be defined.

Each linear gate structure 205, or segment thereof, is devoid of asubstantial change in direction along its length. In one embodiment, asubstantial change in direction of a linear gate structure 205, orsegment thereof, exists when the width 216 of the linear gate structure205 at any point thereon changes by more than 50% of the nominal width216 of the linear gate structure 205 along its entire length. In anotherembodiment, a substantial change in direction of a linear gate structure205, or segment thereof, exists when the width 216 of the linear gatestructure 205 changes from any first location on the linear gatestructure 205 to any second location on the linear gate structure 205 bymore than 50% of the width 216 at the first location.

The exemplary wafer portion 200 further includes a number of activeareas 203 for NMOS devices, as denoted by (n+), and a number of activeareas 201 for PMOS devices, as denoted by (p+). As shown in thecross-section view A-A of FIG. 2B, the n+ active areas 203 are disposedwithin a “p well” 211, and the p wells 211 are bordered by shallowtrench isolation (STI) regions 209. It should be appreciated that insome embodiments the p wells 211 can extend under the STI regions 209.The wafer portion 200, including the p wells 211, the STI regions 209and the gate structures 205 thereabove, is defined over a substrate 213,such as a silicon substrate. Additionally, the active area regions201/203 between the sidewalls 215 of each gate structure 205 can bedefined to have an exposed conductive surface 207. In one embodiment,the exposed conductive surface 207 is formed of metal, metal silicide,or a combination thereof. For example, in one embodiment, a salicideprocess is performed to form a nickel silicide as the exposed conductivesurface 207 present over portions of the active area regions 201/203.

Additionally, the wafer portion 200 can include a thin, e.g., 200-300angstroms thick, etch stop and/or stress liner conformally disposed overits top surface, i.e., conformally disposed over the upper exposedsurfaces of the substrate 213, STI regions 209, active area regions201/203, and gate structures 205. For clarity purposes, the etch stopand/or stress liner is not shown in FIGS. 2A-24B. However, it should beunderstood that such a conformal layer can be present, if appropriate.

Although the wafer portion 200 provided for the SSA contact process hasbeen described in some detail in FIGS. 2A-2C, it should be understoodthat the SSA contact process is not restricted to the specificallydisclosed features of the exemplary wafer portion 200. In otherembodiments, the SSA contact process described herein can be used todefined contacts on a semiconductor wafer portion that includes eithermore or less features than what are explicitly disclosed herein withregard to the exemplary wafer portion 200, so long as the top surface222 and/or top region 217 of each gate structure is capable ofreflecting photons.

With reference back to FIG. 1B, from the operation 115, the methodproceeds with an operation 117 for depositing a photon absorption layer301 over the wafer portion 200. In one embodiment the photon absorptionlayer 301 is formed of amorphous carbon. However, it should beunderstood that in other embodiments the photon absorption layer 301 canbe formed from essentially any material that has a sufficiently strongphoton absorption property and has adequate chemical, structural,thermal, and electrical properties as required for successfulmanufacture and operation of the semiconductor device formed on thewafer portion 200. In one embodiment, the sufficiently strong photonabsorption property of the photon absorption layer 301 material isevidenced by a minimal backscattering of photons incident upon a surfaceof the photon absorption layer 301 material.

FIG. 3 is an illustration showing the photon absorption layer 301deposited over the wafer portion 200, in accordance with one embodimentof the present invention. The photon absorption layer 301 is initiallydeposited to fill the regions between the gate structures 205, and toextend up to a level above the top surfaces 222 of the gate structures205. An operation 119 is then performed to remove an upper portion ofthe photon absorption layer 301 so as to expose the top surfaces 222 ofthe gate structures 205. FIG. 4 is an illustration showing the upperportion of the photon absorption layer 301 removed to expose the topsurfaces 222 of the gate structures 205, in accordance with oneembodiment of the present invention.

In various embodiments, the removal of the upper portion of the photonabsorption layer 301 in operation 119 can be performed using an etchingprocess, a chemical mechanical planarization (CMP) process, or acombination thereof. It should be understood that through operations 117and 119, the photon absorption layer 301 is deposited between the gatestructures 205 so as to substantially cover an area of the wafer portion200 present between the gate structures 205 with the photon absorptionlayer 301, while leaving the top surface 222 of each gate structure 205uncovered. In other words, following operation 119, the photonabsorption layer 301 fills regions adjacent to each gate structure 205so as to contact the side surfaces 220 of each gate structure 205without covering the top surface 222 of each gate structure 205.

Following operation 119, an operation 121 is performed to deposit adielectric layer 501, i.e., a pre-metal dielectric layer, over the waferportion 200. FIG. 5 is an illustration showing the dielectric layer 501deposited over the wafer portion 200, in accordance with one embodimentof the present invention. The dielectric layer 501 is deposited overboth the photon absorption layer 301 and the top surface 222 of eachgate structure 205. In one embodiment, the dielectric layer 501 isformed of an electrically insulating oxide material. However, it shouldbe understood that the SSA contact fabrication process is not limited touse with a specific type of dielectric layer 501. The dielectric layer501 can be formed from essentially any material, or stack of materials,having adequate chemical, structural, thermal, and electrical propertiesas required for successful manufacture and operation of thesemiconductor device formed on the wafer portion 200. Additionally, aspart of operation 121, an upper surface 503 of the deposited dielectriclayer 501 is substantially planarized. In one embodiment, planarizationof the dielectric layer 501 upper surface 503 is performed using a CMPprocess. However, in other embodiments, essentially any technique can beused to planarize the dielectric layer 501, so long as the technique iscompatible with the materials present on the wafer portion 200.

With reference back to FIG. 1A, the method proceeds from the operation101 to an operation 103 in which first hard mask portions 601A areformed directly over the gate structures 205. The term “first” as usedherein with regard to the first hard mask portions 601A, distinguishes amaterial type used to form the first hard mask portions 601A. As will bediscussed later, second hard mask filaments 1101A are also used in theSSA fabrication process. The term “second” as used herein with regard tothe second hard mask filaments 1101A, distinguishes a material type usedto form the second hard mask filaments 1101A, that is different from the“first” material type used to form the first hard mask portions 601A. Inoperation 103, the first hard mask portions 601A are formed over acorresponding number of underlying gate structures such that each firsthard mask portion 601A vertically shadows a respective one of theunderlying gate structures 205.

FIG. 1C is an illustration showing an expanded view of operation 103, inaccordance with one embodiment of the present invention. As shown inFIG. 1C, operation 103 includes an operation 123 for depositing a firsthard mask layer 601 over the wafer portion 200. More specifically, thefirst hard mask layer 601 is deposited over the dielectric layer 501. Anoperation 125 is then performed to deposit a negative photoresist layer603 over the first hard mask layer 601. FIG. 6 is an illustrationshowing the first hard mask layer 601 deposited over the dielectriclayer 501, and the negative photoresist layer 603 deposited over thefirst hard mask layer 601, in accordance with one embodiment of thepresent invention. The first hard mask layer 601 can be defined byessentially any suitable hard mask material. For example, in someembodiments, the first hard mask layer 601 can be defined as an advancedpatterning film (APF) or as a SiON hard mask. Also, the first hard masklayer 601 can be deposited on the wafer portion 200 using essentiallyany hard mask deposition technique. For example, in one embodiment, thefirst hard mask layer 601 is deposited using a chemical vapor deposition(CVD) process.

A negative photoresist material is characterized in that portions of thenegative photoresist material that are sufficiently exposed to a lightsource will made insoluble, i.e., non-removable, in the presence of adeveloper solution, and underexposed portions of the negativephotoresist material will be remain soluble, i.e., removable, in thepresence of the developer solution. The negative photoresist layer 603can be defined by essentially any type of negative photoresist material,e.g., photosensitive polymer, so long as the light exposure thresholdfor cross-linking of the negative photoresist material is suitable foruse with a given light source, such that more than a forward exposure ofthe negative photoresist material to the given light source is requiredfor cross-linking of the negative photoresist material. For example, thelight exposure threshold of the negative photoresist material is suchthat a transmission of collimated, incoherent light from the given lightsource through an upper surface 605 of the negative photoresist layer603 to a lower surface 607 of the negative photoresist layer 603, i.e.,forward exposure, is not sufficient to cross-link the negativephotoresist material.

However, the light exposure threshold of the negative photoresistmaterial is such that the forward exposure of the negative photoresistmaterial combined with a reflective exposure of the negative photoresistmaterial, i.e., exposure to light reflected upward from below the lowersurface 607 of the negative photoresist layer 603, is sufficient tocross-link the negative photoresist material. Also, the characteristicsof the light, e.g., intensity, duration, wavelength, etc., incident uponthe negative photoresist layer 603 can be controlled in conjunction withthe light exposure threshold of the negative photoresist material suchthat a specific amount of reflective exposure of the negativephotoresist material is required for cross-linking of the negativephotoresist material. Additionally, it should be understood that thenegative photoresist layer 603 can be deposited on the wafer portion 200using essentially any photoresist deposition technique, such as spin-ondeposition.

From the operation 125, the method proceeds with an operation 127 forexposing and developing the negative photoresist layer 603, so as toonly leave negative photoresist portions that vertically overlie gatestructures 205. In one embodiment, operation 125 is performed byuniformly exposing the negative photoresist layer 603 to verticallycollimated, incoherent light, whereby the light passes through thenegative photoresist layer 603 to be absorbed by the photon absorptionlayer 301, and to be reflected by the top surface 222/top region 217 ofthe gate structures 205. FIG. 7 is an illustration showing the exposureof the wafer portion 200 to the vertically collimated, incoherent light,in accordance with one embodiment of the present invention. The uniformexposure of the negative photoresist layer 603 to the verticallycollimated, incoherent light is depicted by the downward pointing arrowswithin bracket 701. Reflection of the light, i.e., upward reflection, isdepicted by the upward pointing arrows within brackets 703. It should beappreciated that use of incoherent light serves to prevent formation ofstanding light waves.

Because both forward and reflected exposures of the negative photoresistlayer 603 are required to cross-link the negative photoresist, onlythose portions of negative photoresist that vertically overlie thereflective top surfaces 222/top regions 217 of the gate structures willbe cross-linked. Also, it should be appreciated that because the lightis vertically collimated to be normally, i.e., perpendicularly, incidentupon the top surfaces 222 of the gate structures 205, which aresubstantially horizontal, only those portions of the negativephotoresist layer 603 that are located vertically over the gatestructures 205 will be subjected to substantial reflective exposure ofthe light.

Following exposure of the negative photoresist layer 603 to the light,the negative photoresist layer 603 is developed to remove thenon-cross-linked portions of the negative photoresist layer 603. Invarious embodiments, essentially any photoresist development techniquesuitable for use with the particular negative photoresist material canbe utilized. For example, in one embodiment, an acid etch can be used toremove the non-cross-linked portions of the negative photoresist layer603. FIG. 8 is an illustration showing the wafer portion 200 followingremoval of the non-cross-linked portions of the negative photoresistlayer 603, in accordance with one embodiment of the present invention.As shown in FIG. 8, exposure and development of the negative photoresistlayer 603 in operation 127 leaves the negative photoresist portions603A, such that each negative photoresist portion 603A verticallyoverlies a respective one of the underlying gate structures 205.

Following operation 127, the method proceeds with an operation 129 forremoving portions of the first hard mask layer 601 that are notprotected by the negative photoresist portions 603A, thereby forming thefirst hard mask portions 601A directly over the gate structures 205. Inone embodiment, operation 129 is performed using a vertically biasedetching process, such that the portions of the first hard mask layer 601that are not protected by the negative photoresist portions 603A areremoved in a substantially top-down manner. However, it should beunderstood that other techniques can be used to remove the portions ofthe first hard mask layer 601 that are not protected by the negativephotoresist portions 603A, so long as a width 901 of the remaining firsthard mask portions 601A substantially matches a width 903 of thenegative photoresist portions 603A. In other words, undercutting of thefirst hard mask portions 601A relative to the negative photoresistportions 603A should be minimized to the extent possible.

FIG. 9 is an illustration showing the wafer portion 200 followingremoval of the unprotected portions of the first hard mask layer 601, inaccordance with one embodiment of the present invention. As shown inFIG. 9, removal of the unprotected portions of the first hard mask layer601 in operation 129 leaves the first hard mask portions 601A, such thateach first hard mask portion 601A vertically shadows a respective one ofthe underlying gate structures 205. It should be understood thatvertical shadowing of a given underlying gate structure 205 by a givenfirst hard mask portion 601A is defined by the given first hard maskportion 601A having the substantially same horizontal cross-section sizeand shape as the given underlying gate structure 205. The horizontalcross-section size and shape refers to the size and shape of thefeature, i.e., gate structure 205 or first hard mask portion 601A, whencut in a horizontal plane substantially parallel to the horizontalsurface of the substrate 213. It should be further appreciated that thehorizontal width 901 of each first hard mask portion 601A issubstantially the same as the horizontal width of the top surface222/top region 217 of the underlying gate structure 205.

Following the operation 129, the method proceed with an operation 131for removing the remaining negative photoresist portions 603A. Removalof the remaining negative photoresist portions 603A can be performedusing essentially any photoresist stripping technique, e.g., chemicalstripping, ashing, etc. FIG. 10 is an illustration showing the waferportion 200 following removal of the remaining negative photoresistportions 603A, in accordance with one embodiment of the presentinvention.

With reference back to FIG. 1A, the method proceeds from the operation103 to an operation 105 in which the second hard mask filaments 1101Aare formed adjacent to the first hard mask portions 601A. FIG. 1D is anillustration showing an expanded view of operation 105, in accordancewith one embodiment of the present invention. As shown in FIG. 1D,operation 105 includes an operation 133 for conformally depositing asecond hard mask layer 1101 over the wafer portion 200. FIG. 11 is anillustration showing the second hard mask layer 1101 conformallydeposited over the wafer portion 200, in accordance with one embodimentof the present invention. As shown in FIG. 11, the second hard masklayer 1101 is conformally deposited over both the dielectric layer 501and the first hard mask portions 601A.

The second hard mask layer 1101 can be defined by essentially anysuitable hard mask material, so long as the second hard mask material isdifferent from the first hard mask material used to form the first hardmask portions 601A. More specifically, the second hard mask materialshould have an etching selectivity different than that of the first hardmask material, such that the first hard mask material can be etchedwithout substantially etching the second hard mask material. Forexample, in one embodiment, the second hard mask layer 1101 can beformed of a nitride material. Also, the second hard mask layer 1101 canbe deposited on the wafer portion 200 using essentially any hard maskdeposition technique. For example, in one embodiment, the second hardmask layer 1101 is conformally deposited using a chemical vapordeposition (CVD) process.

Following the operation 133, an operation 135 is performed to removeportions of the second hard mask layer 1101 to leave second hard maskfilaments 1101A adjacent to the first hard mask portions 601A. FIG. 12is an illustration showing the second hard mask filaments 1101A adjacentto the first hard mask portions 601A, in accordance with one embodimentof the present invention. The second hard mask filaments 1101A areessentially defined as sidewall spacers adjacent to the first hard maskportions 601A, such that each side surface of each first hard maskportion 601A has an adjoining second hard mask filament 1101A. In oneembodiment, a horizontal width 1201 of each second hard mask filament1101A, as measured perpendicular to the sidewall of its adjoining firsthard mask portion 601A, is defined to be substantially the same. Also,in one embodiment, a vertical cross-section profile of each exposedsidewall 1203 of each second hard mask filament 1101A is defined to besubstantially vertical. However, in other embodiments, the verticalcross-section profile of the exposed sidewalls 1203 of the hard maskfilaments 1101A may other than substantially vertical. For example, inone embodiment, the vertical cross-section profile of the exposedsidewall 1203 of the second hard mask filament 1101A can be tapered suchthat the second hard mask filament 1101A is thicker at its bottom, i.e.,at the dielectric layer 501, relative to its top.

In one embodiment, the second hard mask filaments 1101A are formed byetching the second hard mask layer 1101, such that horizontal surfacesof the second hard mask layer 1101 are preferentially etched relative tothe vertical surfaces of the second hard mask layer 1101. It should beunderstood, however, that other techniques can be utilized to form thesecond hard mask filaments 1101A from the second hard mask layer 1101,such that each second hard mask filament 1101A is formed as a hard maskspacer extending out from the sidewalls of the first hard mask portions601A. Because the width 901 of a given first hard mask portion 601A issubstantially equal to the width of the top surface 222 of theunderlying gate structure 205, a combined width of the given first hardmask portion 601A and its adjoining second hard mask filaments 1101A isgreater than the width of the underlying gate structure 205. Also, itshould be understood that a perpendicular spacing 1205 between facingexposed side surfaces of a given pair of neighboring second hard maskfilaments 1101A effectively defines a width of an active area contact tobe formed between the given pair of neighboring second hard maskfilaments 1101A. Therefore, because the first hard mask portion 601Avertically shadows the underlying gate structure 205, the width 1201 ofeach second hard mask filament effectively defines an active areacontact-to-gate structure 205 spacing.

With reference back to FIG. 1A, the method proceeds from the operation105 to an operation 107 in which passages are etched for active areacontacts. FIG. 1E is an illustration showing an expanded view ofoperation 107, in accordance with one embodiment of the presentinvention. As shown in FIG. 1E, operation 107 includes an operation 137for depositing a positive photoresist layer 1301 over the wafer portion200. FIG. 13 is an illustration showing the positive photoresist layer1301 deposited over the wafer portion 200, in accordance with oneembodiment of the present invention. As shown in FIG. 13, the positivephotoresist layer 1301 is deposited over both the exposed dielectriclayer 501 portions, the exposed first hard mask portions 601A, and theexposed second hard mask filaments 1101A. The positive photoresist layer1301 can be defined by essentially any type of positive photoresistmaterial. The positive photoresist material is characterized in thatportions of the positive photoresist material that are sufficientlyexposed to a light source will made soluble, i.e., removable, in thepresence of a developer solution, and underexposed portions of thepositive photoresist material will remain insoluble, i.e.,non-removable, in the presence of the developer solution.

Following operation 137, an operation 139 is performed to pattern thepositive photoresist layer 1301 with an active area contact mask. Morespecifically, the positive photoresist layer 1301 is patterned toinclude a substantially linear opening through the positive photoresistlayer 1301, extending from one first hard mask portion 601A to aneighboring first hard mask portion 601A in a direction substantiallyperpendicular to the length of each of the neighboring first hard maskportions 601A. The patterning of the positive photoresist layer 1301 canbe performed using essentially any conventional photolithographytechnique.

FIG. 14A is an illustration showing an example active area contact maskused to pattern the positive photoresist layer 1301, in accordance withone embodiment of the present invention. The active area contact maskincludes a number of linear openings 1401. Each linear opening 1401represents an area where the positive photoresist layer 1301 is removedto expose the underlying dielectric layer 501, first hard mask portions601A, and second hard mask filaments 1101A. Although, the linearopenings 1401 are shown as “ideal” rectangular-shaped openings, itshould be understood that the actual linear openings 1401 may havesomewhat rounded ends. However, it should be noted that the rounded endswill lie above the first hard mask portions 601A and/or the second hardmask filaments 1101A, but not above the dielectric layer 501 portionthat extends perpendicularly between the second hard mask filaments1101A.

FIG. 14B is an illustration showing the vertical cross-section view A-Aof the wafer portion 200 with the patterned positive photoresist layer1301, in accordance with one embodiment of the present invention.Substantially rectangular areas 1403 of the dielectric layer 501 areexposed between the neighboring second hard mask filaments 1101A withinthe linear openings 1401. The substantially rectangular areas 1403 ofthe dielectric layer 501 are bounded on two opposing side by the secondhard mask filaments 1101A, and on the other two opposing sides by thelinear opening 1401 of the patterned positive photoresist layer 1301. Itshould be appreciated that the substantially rectangular areas 1403 ofthe dielectric layer 501 represent the horizontal cross-section of theactive area contact to be formed.

Also, it should be appreciated that because the active area contact isto be bounded by the second hard mask filaments 1101A in the linearopenings 1401, and because the linear openings 1401 are “oversized” withrespect to the distance between the sidewalls of the neighboring secondhard mask filaments 1101A, there is some flexibility provided in theindexing of the active area contact mask to the wafer portion 200 whenpatterning the positive photoresist layer 1301. For example, if thelinear opening 1401 is offset slightly in its direction of extentbetween the first hard mask portions 601A, the substantially rectangulararea 1403 of exposed dielectric layer 501 will be unaffected.

Following the operation 139, the method proceeds with an operation 141for etching passages 1501 for the active area contacts. FIG. 15 is anillustration showing the vertical cross-section view A-A of the waferportion 200 with the passages 1501 etched therein, in accordance withone embodiment of the present invention. The passages 1501 for theactive area contacts are etched downward through the exposed,substantially rectangular areas 1403 of the dielectric layer 501 withinthe linear openings 1401. In one embodiment, the passages 1501 for theactive area contacts are etched in a substantially vertical manner, suchthat sidewalls of the passages 1501 extend in a substantially verticalmanner downward from the periphery of the substantially rectangularareas 1403 of the dielectric layer 501 within the linear openings 1401.Although, the sidewalls of the passages 1501 ideally extend downward ina substantially vertical manner, it should be understood that thesidewalls of the passages 1501 can be slightly tapered. For example, inone embodiment, the sidewalls of a given passage 1501 can be taperedsuch that the rectangular opening of the given passage 1501 is slightlysmaller at its bottom end relative to its top end.

In one embodiment, a vertically biased etching process can be used toform the passages 1501 for the active area contacts. The passages 1501are etched downward through the underlying portion of the dielectriclayer 501, and the underlying portion of the photon absorption layer 301to reach the conductive material, e.g., silicide, present at the top ofthe underlying active area, or to reach an etch stop layer present overthe underlying active area. It should be understood that during theetching of the passages 1501 for the active area contacts, the secondhard mask filaments 1101A are etched very slowly so as to not besubstantially removed.

Following the operation 141, an operation 143 is performed to remove thepatterned photoresist layer 1301 from the wafer portion 200. FIG. 16 isan illustration showing the wafer portion 200 following removal of thepatterned photoresist layer 1301, in accordance with one embodiment ofthe present invention. The patterned photoresist layer 1301 can beremoved using essentially any photoresist stripping technique, e.g.,chemical stripping, ashing, etc.

With reference back to FIG. 1A, the method proceeds from the operation107 to an operation 109 in which passages are etched for gate contacts.FIG. 1F is an illustration showing an expanded view of operation 109, inaccordance with one embodiment of the present invention. As shown inFIG. 1F, operation 109 includes an operation 145 for depositing apositive photoresist layer 1701 over the wafer portion 200. FIG. 17 isan illustration showing the positive photoresist layer 1701 depositedover the wafer portion 200, in accordance with one embodiment of thepresent invention. As shown in FIG. 17, the positive photoresist layer1701 is deposited over both the exposed dielectric layer 501 portions,the exposed first hard mask portions 601A, the exposed second hard maskfilaments 1101A, and within the active area contact passages 1501previously etched in operation 107. The positive photoresist layer 1701can be defined by essentially any type of positive photoresist material.The positive photoresist material is characterized in that portions ofthe positive photoresist material that are sufficiently exposed to alight source will made soluble, i.e., removable, in the presence of adeveloper solution, and underexposed portions of the positivephotoresist material will remain insoluble, i.e., non-removable, in thepresence of the developer solution.

Following operation 145, an operation 147 is performed to pattern thepositive photoresist layer 1701 with a gate contact mask. Morespecifically, the positive photoresist layer 1701 is patterned toinclude a number of substantially linear openings through the positivephotoresist layer 1701, each extending across a given first hard maskportion 601A and across portions of the two second hard mask filaments1101A adjacent to the given first hard mask portion 601A. Thesubstantially linear opening defined through the positive photoresistlayer 1701 is oriented to extend in a direction substantiallyperpendicular to the length 218 of the underlying gate structure 205over which the linear opening is defined. The patterning of the positivephotoresist layer 1701 can be performed using essentially anyconventional photolithography technique.

FIG. 18A is an illustration showing an example gate contact mask used topattern the positive photoresist layer 1701, in accordance with oneembodiment of the present invention. The gate contact mask includes anumber of linear openings 1801. Each linear openings 1801 representsarea where the positive photoresist layer 1701 is removed to expose theunderlying first hard mask portion 601A, and adjoining portions of thesecond hard mask filaments 1101A. Although, the linear openings 1801 areshown as “ideal” rectangular-shaped openings, it should be understoodthat the actual linear openings 1801 may have somewhat rounded ends.However, it should be noted that the rounded ends of a given linearopening 1801 will lie above the adjoining second hard mask filaments1101A, and will not lie above the first hard mask portion 601A overwhich the given linear opening 1801 extends.

FIG. 18B is an illustration showing the vertical cross-section view A-Aof the wafer portion 200 with the patterned positive photoresist layer1701, in accordance with one embodiment of the present invention.Substantially rectangular areas 1803 of first hard mask portions 601Aare exposed between the neighboring second hard mask filaments 1101Awithin the linear openings 1801. The substantially rectangular areas1803 of the first hard mask portions 601A are bounded on two opposingside by the second hard mask filaments 1101A, and on the other twoopposing sides by the linear opening 1801 of the patterned positivephotoresist layer 1701. It should be appreciated that the substantiallyrectangular area 1803 of the first hard portion 601A, as exposed in thelinear opening 1801, represents the horizontal cross-section of the gatecontact to be formed. Also, it should be appreciated that because thegate contact is to be bounded by the second hard mask filaments 1101A inthe linear opening 1801, and because the linear opening 1801 is“oversized” with respect to the width of the first hard mask portion601A, there is some flexibility provided in the indexing of the gatecontact mask to the wafer portion 200 when patterning the positivephotoresist layer 1701. For example, if the linear opening 1801 isoffset slightly in its direction of extent between the second hard maskfilaments 1101A, the substantially rectangular area 1803 of the exposedfirst hard mask portion 601A will be unaffected.

Following the operation 147, the method proceeds with an operation 149for etching passages 1901 for the gate contacts. FIG. 19 is anillustration showing the vertical cross-section view A-A of the waferportion 200 with the passages 1901 etched therein, in accordance withone embodiment of the present invention. The passages 1901 for the gatecontacts are etched downward through the exposed, substantiallyrectangular areas 1803 of the first hard mask portion 601A within thelinear openings 1801. It should be appreciated that because thematerials of the first hard mask portion 601A and the second hard maskfilament 1101A are different, these material can be selected to have asubstantially different etching selectivity with respect to a givenetching process. For example, the first hard mask portion 601A may bedefined to etch ten times faster than the second hard mask filaments1101A. Therefore, during the particular etching process to be performedin operation 149, the exposed first hard mask portion 601A is defined tobe preferentially etched without substantially affecting the neighboringexposed second hard mask filaments 1101A. It should be understood thatduring the etching of the passages 1901 for the gate contacts, thesecond hard mask filaments 1101A are etched very slowly so as to not besubstantially removed.

In one embodiment, the passages 1901 for the gate contacts are etched ina substantially vertical manner, such that sidewalls of the passages1901 extend in a substantially vertical manner downward from theperiphery of the substantially rectangular areas 1803 of the exposedfirst hard mask portion 601A within the linear openings 1801. However,it should be understood that the sidewalls of the passages 1901 are notrequired to extend downward in a substantially vertical manner. Forexample, in one embodiment, the sidewalls of the passages 1901 can beslightly tapered, such that the rectangular opening of the given passage1901 is slightly smaller at its bottom end relative to its top end. Inone embodiment, a vertically biased etching process can be used to formthe passages 1901 for the gate contacts. The passages 1901 are etcheddownward through the first hard mask portion 601A to reach the topsurface 222 of the underlying gate structure 205, or to reach an etchstop layer present over the underlying gate structure 205.

Following the operation 149, an operation 151 is performed to remove thepatterned photoresist layer 1701 from the wafer portion 200. FIG. 20 isan illustration showing the wafer portion 200 following removal of thepatterned photoresist layer 1701, in accordance with one embodiment ofthe present invention. The patterned photoresist layer 1701 can beremoved using essentially any photoresist stripping technique, e.g.,chemical stripping, ashing, etc.

With reference back to FIG. 1A, the method proceeds from the operation109 to an operation 111 in which the first hard mask portions 601A andthe second hard mask filaments 1101A are removed from the wafer portion200. FIG. 21 is an illustration showing the wafer portion 200 followingremoval of the first hard mask portions 601A and the second hard maskfilaments 1101A, in accordance with one embodiment of the presentinvention. Operation 111 can be performed using essentially any hardmask removal technique. For example, in one embodiment the first hardmask portions 601A and the second hard mask filaments 1101A are removedusing a wet stripping technique. It should also be understood that theoperation 111 includes removal of any exposed etch stop layer, ifpresent at the bottoms of the passages 1501 and 1901.

The method proceeds from operation 111 to an operation 113 in whichactive area contacts 2301 and gate contacts 2303 are disposed within thepassages 1501 and 1901, respectively. FIG. 1G is an illustration showingan expanded view of operation 113, in accordance with one embodiment ofthe present invention. As shown in FIG. 1G, operation 113 includes anoperation 153 for depositing a metal layer 2201 over the wafer portion200. FIG. 22 is an illustration showing the vertical cross-section viewA-A of the wafer portion 200 with the metal layer 2201 depositedthereon, in accordance with one embodiment of the present invention. Inone embodiment, the metal layer 2201 is deposited as a liner followed bya metal fill. For example, in one embodiment, the metal layer 2201 isformed by first depositing a TiN liner over the wafer portion 200 usinga chemical vapor deposition (CVD) process or a physical vapor deposition(PVD) process. Then, a tungsten (W) fill layer is deposited over the TiNliner using a CVD process. In this embodiment, the TiN liner isrelatively thin, while the W fill layer completely fills the contactpassages 1501 and 1901.

Following the operation 153, an operation 155 is performed to removalexcess metal from the top of the wafer portion 200, so as to leave thetop surface of the dielectric layer exposed 501 and the contact passages1501 and 1901 filled with metal. For example, in the TiN liner/W fillembodiment, a CMP process can be used to perform operation 155 so as toremove the W fill layer and the TiN liner from the top surface of thedielectric layer 501. FIG. 23 is an illustration showing the verticalcross-section view A-A of the wafer portion 200 with the excess metallayer 2201 removed to leave the active area contacts 2301 and the gatecontacts 2303, in accordance with one embodiment of the presentinvention. Following completion of operation 113, i.e., followingcompletion of the SSA contact fabrication process, fabrication of thewafer portion 200 can continue with fabrication of a metalization layerover the dielectric layer 501.

FIG. 24A is an illustration showing a top view of the wafer portion 200following formation of the active area contacts 2301 and gate contacts2303, in accordance with one embodiment of the present invention. Itshould be appreciated that each active area contact 2301 issubstantially centered between its neighboring gate structures 205.Also, it should be appreciated that each gate contact 2303 is defined tosubstantially cover the width of the underlying gate structure 205without extending substantially beyond either of the side surfaces ofthe underlying gate structure 205. Hence, due to their direct referencefrom the as-fabricated gate structures 205, the active area contacts2301 and the gate contacts 2303 are considered to be super-self-aligned(SSA) contacts with respect to the gate structures 205. Additionally, itshould be appreciated that the horizontal cross-section of each activearea contact and each gate contact is substantially rectangular inshape.

FIG. 24B is an illustration showing an expanded view of an area 2401, ascalled out in FIG. 24A, in accordance with one embodiment of the presentinvention. As shown in FIG. 24B, the active area contact 2301 issubstantially centered between its neighboring gate structures 205, suchthat a substantially equal gate-to-active area contact spacing (SGC)exists on each side the active area contact 2301. As previouslydiscussed, the gate-to-active area contact spacing (SGC) is defined bythe width of the second hard mask filament 1101A, as measured in thehorizontal direction perpendicular to the length 218 of the gatestructure 205. As shown in FIG. 24B, the gate pitch (PGA) is equal tothe sum of the gate width (WGA), the active area contact width (WCT),and twice the gate-to-active area contact spacing (SGC).

While this invention has been described in terms of several embodiments,it will be appreciated that those skilled in the art upon reading thepreceding specifications and studying the drawings will realize variousalterations, additions, permutations and equivalents thereof. Therefore,it is intended that the present invention includes all such alterations,additions, permutations, and equivalents as fall within the true spiritand scope of the invention.

What is claimed is:
 1. A method for fabricating an active area contactwithin a semiconductor wafer, comprising: forming a number of first hardmask portions over a corresponding number of underlying gate structuressuch that each first hard mask portion vertically shadows a respectiveone of the underlying gate structures; forming a number of second hardmask filaments adjacent to each of the number of first hard maskportions such that a combined width of each first hard mask portion andits adjoining second hard mask filaments is greater than a width of therespective underlying gate structure, and such that a width of eachsecond hard mask filament defines an active area contact-to-gatestructure spacing; etching a passage between facing surfaces ofneighboring second hard mask filaments and through a depth of thesemiconductor wafer to an active area; and depositing an electricallyconductive material within the passage to form the active area contact.2. A method for fabricating an active area contact within asemiconductor wafer as recited in claim 1, wherein each gate structureis configured as a linear gate structure having a top surface,substantially parallel side surfaces, a width defined perpendicularlybetween the side surfaces, and a length extending perpendicular to thewidth along the top surface, and wherein each gate structure is devoidof a substantial change in direction along its length.
 3. A method forfabricating an active area contact within a semiconductor wafer asrecited in claim 1, wherein the vertical shadowing of a given underlyinggate structure by a given first hard mask portion is defined by thegiven first hard mask portion having a substantially same horizontalcross-section size and shape as the given underlying gate structure. 4.A method for fabricating an active area contact within a semiconductorwafer as recited in claim 1, further comprising: depositing a photonabsorption layer between the gate structures so as to substantiallycover an area present between the gate structures with the photonabsorption layer while leaving a top surface of each gate structureuncovered; and depositing a dielectric layer over both the photonabsorption layer and the top of each gate structure, wherein the numberof first hard mask portions and the number of second hard mask filamentsare formed on the dielectric layer.
 5. A method for fabricating anactive area contact within a semiconductor wafer as recited in claim 4,wherein forming the number of first hard mask portions over thecorresponding number of underlying gate structures includes, depositinga first hard mask layer over the dielectric layer, depositing a negativephotoresist layer over the first hard mask layer, uniformly exposing thenegative photoresist layer to vertically collimated incoherent light,whereby light is absorbed by the photon absorption layer and reflectedby the top surface of the underlying gate structures so as to onlycross-link negative photoresist portions that vertically overlie gatestructures, removing non-cross-linked negative photoresist such thatnegative photoresist portions that vertically overlie gate structuresremain, removing portions of the first hard mask layer that are notprotected by the remaining negative photoresist portions, therebyforming the number of first hard mask portions, and removing theremaining negative photoresist portions.
 6. A method for fabricating anactive area contact within a semiconductor wafer as recited in claim 4,wherein forming the number of second hard mask filaments adjacent toeach of the number of first hard mask portions includes, depositing asecond hard mask layer over the dielectric layer and the number of firsthard mask portions, and removing portions of the second hard mask layerto leave a second hard mask filament adjacent to each side surface ofeach of the number of first hard mask portions.
 7. A method forfabricating an active area contact within a semiconductor wafer asrecited in claim 4, wherein etching the passage includes, depositing apositive photoresist layer over the dielectric layer, the number offirst hard mask portions, and the number of second hard mask filaments,patterning the positive photoresist layer to include a linear openingextending from one first hard mask portion to a neighboring first hardmask portion in a direction substantially perpendicular to each of thefirst hard mask portions, whereby a substantially rectangular area ofthe dielectric layer is exposed between neighboring second hard maskfilaments in the linear opening, and etching the passage downwardthrough the rectangular area of the dielectric layer.
 8. A method forfabricating a gate contact within a semiconductor wafer, comprising:forming a first hard mask portion over a gate structure within a sectionof the semiconductor wafer, wherein the first hard mask portionvertically shadows the gate structure, and wherein the first hard maskportion includes substantially vertical side surfaces; forming a secondhard mask filament adjacent to each side surface of the first hard maskportion; etching a passage through the first hard mask portion andthrough a depth of the semiconductor wafer to a top surface of the gatestructure, whereby surfaces of the second hard mask filaments adjacentto the vertical side surfaces of the first hard mask portion arerevealed through etching of the first mask portion and define sidesurfaces of the passage; and depositing an electrically conductivematerial within the passage to form the gate contact.
 9. A method forfabricating a gate contact as recited in claim 8, wherein the verticalshadowing of the gate structure by the first hard mask portion isdefined by the first hard mask portion having a substantially samehorizontal cross-section size and shape as the gate structure.
 10. Amethod for fabricating a gate contact as recited in claim 8, furthercomprising: depositing a photon absorption layer to fill regionsadjacent to the gate structure so as to contact the gate structurewithout covering a top surface of the gate structure; and depositing adielectric layer over both the photon absorption layer and the gatestructure, wherein the first hard mask portion and the second hard maskfilaments are formed on the dielectric layer.
 11. A method forfabricating a gate contact as recited in claim 10, wherein forming thefirst hard mask portion over the gate structure includes, depositing afirst hard mask layer over the dielectric layer, depositing a negativephotoresist layer over the first hard mask layer, uniformly exposing thenegative photoresist layer to vertically collimated incoherent light,whereby light is absorbed by the photon absorption layer and reflectedby the top surface of the gate structure so as to only cross-link anegative photoresist portion that vertically overlies the gatestructure, removing non-cross-linked negative photoresist such that onlythe negative photoresist portion that vertically overlies the gatestructure remains, removing portions of the first hard mask layer thatare not protected by the remaining negative photoresist portion to formthe first hard mask portion, and removing the remaining negativephotoresist portion.
 12. A method for fabricating a gate contact asrecited in claim 10, wherein forming the second hard mask filamentadjacent to each side surface of the first hard mask portion includes,depositing a second hard mask layer over the dielectric layer and thefirst hard mask portion, and removing portions of the second hard masklayer to leave a respective second hard mask filament adjacent to eachside surface of the first hard mask portion.
 13. A method forfabricating a gate contact as recited in claim 10, wherein etching thepassage includes, depositing a positive photoresist layer over thedielectric layer, the first hard mask portion, and the second hard maskfilaments, patterning the positive photoresist layer to include a linearopening extending across the first hard mask portion and across portionsof each second hard mask filament adjacent to the first hard maskportion, whereby a substantially rectangular area of the first hard maskportion is exposed between the portions of each second hard maskfilament in the linear opening, and etching the passage downward throughthe rectangular area of the first hard mask portion.
 14. A method forfabricating a gate contact as recited in claim 13, wherein an etchingselectivity of the first hard mask portion is different from an etchingselectivity of the second hard mask filaments, such that the first hardmask portion can be etched without substantially etching the second hardmask filaments.
 15. A method for fabricating an active area contact anda gate contact within a semiconductor wafer, comprising: depositing aphoton absorption layer between gate structures within a section of thesemiconductor wafer so as to substantially cover an area present betweengate structures with the photon absorption layer while leaving a topsurface of each gate structure uncovered; depositing a dielectric layerover both the photon absorption layer and the top of each gate structurewithin the section of the semiconductor wafer; forming a number of firsthard mask portions on the dielectric layer and over the gate structureswithin the section of the semiconductor wafer, whereby each first hardmask portion vertically shadows a respective one of the gate structures,and wherein each first hard mask portion includes substantially verticalside surfaces; forming a second hard mask filament adjacent to eachvertical side surface of each first hard mask portion, each second hardmask filament having an exposed side surface, wherein a width of eachsecond hard mask filament defines an active area contact-to-gatestructure spacing; etching a first passage between facing exposed sidesurfaces of a given pair of neighboring second hard mask filaments andthrough a depth of the semiconductor wafer to an active area; etching asecond passage through a given first hard mask portion and through adepth of the semiconductor wafer to a top surface of the gate structureunderlying the given first hard mask portion, whereby surfaces of thesecond hard mask filaments adjacent to the vertical side surfaces of thegiven first hard mask portion are revealed through etching of the givenfirst mask portion and define side surfaces of the second passage; anddepositing an electrically conductive material within both the first andsecond passages to respectively form the active area contact and thegate contact.
 16. A method for fabricating an active area contact and agate contact within a semiconductor wafer as recited in claim 15,wherein the photon absorption layer is an amorphous carbon absorptionlayer.
 17. A method for fabricating an active area contact and a gatecontact within a semiconductor wafer as recited in claim 15, whereinforming the number of first hard mask portions includes, depositing afirst hard mask layer over the dielectric layer, and performing aphotolithography process utilizing light absorption by the photonabsorbing layer and light reflection by the top surface of each gatestructure to form the number of first hard mask portions from the firsthard mask layer.
 18. A method for fabricating an active area contact anda gate contact within a semiconductor wafer as recited in claim 17,wherein the photolithography process includes, depositing a negativephotoresist layer over the first hard mask layer, uniformly exposing thenegative photoresist layer to vertically collimated incoherent light,whereby light is absorbed by the photon absorption layer between gatestructures and reflected by the top surface of each gate structure so asto only cross-link negative photoresist portions that vertically overliethe gate structures, removing non-cross-linked negative photoresist suchthat only negative photoresist portions that vertically overlie the gatestructures remain, removing portions of the first hard mask layer thatare not protected by the remaining negative photoresist portions to formthe number of first hard mask portions, and removing the remainingnegative photoresist portions.
 19. A method for fabricating an activearea contact and a gate contact within a semiconductor wafer as recitedin claim 15, wherein etching the first passage includes, depositing apositive photoresist layer over the dielectric layer, the first hardmask portions, and the second hard mask filaments, patterning thepositive photoresist layer to include a linear opening extending fromone first hard mask portion to a neighboring first hard mask portion ina direction substantially perpendicular to each of the first hard maskportions, whereby a substantially rectangular area of the dielectriclayer is exposed between neighboring second hard mask filaments in thelinear opening, and etching the first passage downward through therectangular area of the dielectric layer.
 20. A method for fabricatingan active area contact and a gate contact within a semiconductor waferas recited in claim 15, wherein etching the second passage includes,depositing a positive photoresist layer over the dielectric layer, thefirst hard mask portions, and the second hard mask filaments, patterningthe positive photoresist layer to include a linear opening extendingacross a given first hard mask portion and across portions of eachsecond hard mask filament adjacent to the given first hard mask portion,whereby a substantially rectangular area of the given first hard mask isexposed between the portions of each second hard mask filament in thelinear opening, and etching the second passage downward through therectangular area of the given first hard mask portion.